The pilot reported that while taking off behind the towplane, the glider drifted to the left and impacted the left wing of another glider that was parked on the ground close to the runway and positioned such that its left wing was about 7 ft in the air. The pilot lost control of the glider and the glider subsequently impacted the ground coming to rest inverted. The glider sustained substantial damage to the left wing, aft fuselage, and empennage. The parked glider sustained substantial damage to the left wing. The pilot reported that there were no preaccident mechanical failures or malfunctions with the glider that would have precluded normal operation. At the time of the accident, the glider was taking off on runway 09 with wind 110o at 7 knots, gusting to 12 knots. The pilot reported that the accident could have been prevented if they had waited until the other glider had been moved away from the runway before beginning the takeoff.